Japanese Matting As An Excellent Koi Fish Pond Filter Bio-Media

The single biggest reason for the success of well designed vortex or other
filters using Japanese matting is that large amounts of air pumped into the
vortex biological chambers create highly significant turbulence which allows
excellent mass transfer through maximising concentration differences as required
and described above. This happens in conjunction with the simultaneous creation
of large and open surface area structures on which many bacteria can thrive and
grow - perfect conditions. Japanese Matting is successful not because of the
matting per se but what the structure of the matting allows in conjunction with
a vortex type filter design such as ...

Massive air injection through air stones before each matting section.

Very open structure of matting matrix

High flow rate large pump used

Although you cannot see it all solids have been efficiently removed to prevent
clogging of the Japanese matting.

Only a small proportion of pond keepers can afford or really need large Japanese
type matting vortex filters. However if you can afford it then it is one of the best
ways without doubt and no matter what people say it has been proven time and time
again. This is what a vortex filter looks like below they take up large
amounts of space and are difficult to install on a DIY basis.

An USA company markets Matala (the invention of Marc Talloen who I first met in
Germany) that is similar in performance and principle to Japanese matting.

If people try to convince you vortex filters are not highly effective you can be
sure they do NOT really understand what is supposed to happen in a biofilter.

If You cannot afford or don't want to contemplate a vortex filter?
On the assumption that second best has to do then all that has to be considered
is

How do you get more surface area into your
filter?

How do you get more turbulence?

How do you get more oxygen to the interface
where the bacteria and the ammonia meet? and importantly

How do you get rid of solids accumulation, which is not good for your pond?

Look no further than modern pressurized pond filters by Hozelock, Oase and
FishMate. My preference is for the FishMate for the simple reason it contains Alfagrog
which in my opinion is the best low cost way to introduce more area
into any conventional pond filter be it pressurized or otherwise ...
throw away those hair curlers, plastic rings, onion bags and whatever else you
might use. The use of Alfagrog in pressurized pond filters allows these filters
to be extremely small relative to pond volume.
This purpose built ceramic filter medium is coarse and full of interstices
(small holes) allowing massive colonisation on large surface areas for all types
of bacteria required in the biofiltration process.

Because of the high specific surface area (ie surface area per unit volume)
which in the case of Alfagrog 40 amounts to a whopping 43 square metres per
litre filters can be reduced in size which in turn allows higher levels of
turbulence to be achieved or low residence times.
Best of all it is low cost and is easily cleaned.

For comparison purposes 1 litre of Alfagrog 40 has the same specific surface
area as about 100 litres of plastic tubes. It seems hard to believe but it is
true.

But I Was Told The Pond Filter Must Be 1/3rd The Volume Of My Pond

When people say that the filter must be a specific ratio of the pond size then
they are not considering the facts of the situation and are simply repeating
what they have been told and do not understand the principles of biofiltration.
Such advice is not based upon well-reasoned thought. Discard such advice is my
recommendation. On the other hand it is impossible to have too large a filter.
It just costs more money.

At this stage I have to say the following although I risk incurring the wrath of
many people. However hopefully if you have followed my arguments so far you will
undoubtedly agree with me.

Sand filters are bad for ponds but great for swimming pools and can only
remotely be justified as solid removers. They perform little if any
nitrification - poor surface area contact, low levels of turbulence, dead areas
for pathogenic bacteria to accumulate, and low oxygen levels. I strongly believe
there is no place for a sand filter in a pond environment. They are also
extremely costly to run.

If you have reached the stage where you believe you want to understand the
whole process of pond filtration then go through these articles in the order
presented.